title: Downregulation of 14q32 microRNAs in Primary Human Desmoplastic Medulloblastoma.
abstract: Medulloblastoma (MB) is one of the most common pediatric cancers, likely originating from abnormal development of cerebellar progenitor neurons. MicroRNA (miRNA) has been shown to play an important role in the development of the central nervous system. Microarray analysis was used to investigate miRNA expression in desmoplastic MB from patients diagnosed at a young age (1 or 2 years old). Normal fetal or newborn cerebellum was used as control. A total of 84 differentially expressed miRNAs (64 downregulated and 20 upregulated) were found. Most downregulated miRNAs (32/64) were found to belong to the cluster of miRNAs at the 14q32 locus, suggesting that this miRNA locus is regulated as a module in MB. Possible mechanisms of 14q32 miRNAs downregulation were investigated by the analysis of publicly available gene expression data sets. First, expression of estrogen-related receptor-γ (ESRRG), a reported positive transcriptional regulator of some 14q32 miRNAs, was found downregulated in desmoplastic MB. Second, expression of the parentally imprinted gene MEG3 was lower in MB in comparison to normal cerebellum, suggesting a possible epigenetic silencing of the 14q32 locus. miR-129-5p (11p11.2/7q32.1), miR-206 (6p12.2), and miR-323-3p (14q32.2), were chosen for functional studies in DAOY cells. Overexpression of miR-129-5p using mimics decreased DAOY proliferation. No effect was found with miR-206 or miR-323 mimics.
authors.affiliation: Centro Infantil Boldrini , Campinas , Brazil ; Departamento de Genética Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas , Campinas , Brazil.
authors.forename: Danielle Ribeiro
authors.initials: DR
authors.lastname: Lucon
authors.forename: Cristiane de Souza
authors.initials: Cde S
authors.lastname: Rocha
authors.forename: Rogerio Bastos
authors.initials: RB
authors.lastname: Craveiro
authors.forename: Dagmar
authors.initials: D
authors.lastname: Dilloo
authors.forename: Izilda A
authors.initials: IA
authors.lastname: Cardinalli
authors.forename: Denise Pontes
authors.initials: DP
authors.lastname: Cavalcanti
authors.forename: Simone Dos Santos
authors.initials: Sdos S
authors.lastname: Aguiar
authors.forename: Claudia
authors.initials: C
authors.lastname: Maurer-Morelli
authors.forename: Jose Andres
authors.initials: JA
authors.lastname: Yunes
keywords: 14q32 miRNA cluster; ESRRG; desmoplastic medulloblastoma; miR-129-5p; miRNA profile